1. Field of the Invention
The invention relates to a supercharging arrangement for the charge air of an internal combustion engine.
2. The Prior Art
From JP 01 060 717 A a supercharging arrangement for the charge air of an internal combustion engine, in particular of a piston engine, is known which is arranged as a pressure wave machine which is flow-connected with an air-inlet line for the charge air and an exhaust gas line for the combustion gases of the piston engine. The pressure wave machine is provided with a housing which is formed by a charge air face housing, an exhaust gas face housing and a housing part which mutually distances the same. The housing, in particular the charge air face housing and exhaust gas face housing, is provided with flow-in and flow-off ducts. A cell rotor is disposed in the housing which is rotatably held in a bearing arrangement and is provided with several paths of flow which are arranged concentrically with respect to one another and is connected with a rotary drive. Switching members are arranged in the exhaust gas face housing in flow-in ducts for the combustion gases to the paths of flow. The disadvantage in this respect is that a pressure-charged path of flow is flow-connected on the charge air side with flow-off ducts by way of flow-off ducts assigned to the same and the air-inlet line, which flow-off ducts are assigned to a path of flow which is not charged with pressure. In this way the charge air which is compressed via the pressure waves of the combustion gases cannot only penetrate the air-inlet line for the charge air to the piston engine on reaching the charge air face housing, but can also penetrate the other paths of flow which are not charged with pressure waves for example. This causes an undesirable pressure loss and thus a reduction in the efficiency of the pressure wave machine and consequently a more unfavourable controllability of the pressure wave process.
From JP 62 101 850 A a supercharging arrangement for the charge air of a combustion engine is known which is arranged in a flow-connected manner between an air-inlet line for the charge air and an exhaust gas line for the combustion gases. It is arranged as a pressure wave machine and is provided with a cell rotor. The air-inlet line for the charge air is provided on the high-pressure side with a switching member which can be used to change the air inlet stream to the internal combustion engine. The disadvantage in this embodiment is that also in the case of using a cell rotor with several paths of flow which are arranged concentrically with respect to one another it is not possible to prevent that compressed charge air is conducted from a path of flow which is in operation, i.e. it is charged with pressure waves, to another path of flow which is not in operation. As already described above, this leads to an undesirable pressure loss.
GB 2 065 232 A and U.S. Pat. No. 3,011,487 A describe an angular offset of inlet and outlet openings in exhaust gas face housings and charge air face housings. This angular offset can be adjusted to the speed of the internal combustion engine.
A device for supercharging an internal combustion engine is known from DE 26 33 568 C2 in which an exhaust gas turbocharger is connected with the gas-dynamic pressure wave machine which is connected in series on the exhaust gas side and air side and causes a supply of the internal combustion engine with fresh air in two stages. The exhaust gas turbocharger is used for the high-pressure stage and the pressure wave machine for the low-pressure stage. This known device further also provides the intermediate heating of the exhaust gas prior to its supply to the pressure wave machine. This device requires a high amount of technical complexity, as a result of which its application in the low and medium output spectrum of internal combustion engines is not favourable.
From DE 28 44 287 C2 a parallel-flow gas-dynamic pressure wave machine is known which is provided with a cell rotor which is rotatably held in the housing by way of a driving axle and the drive of the cell rotor is performed by way of a belt drive via the crankshaft of the internal combustion engine. The disadvantage in such an embodiment is that the pressure wave machine is operated in direct dependence on the rotational speed of the internal combustion engine, as a result of which the efficiency of the pressure wave machine, particularly in the lower speed range of the internal combustion engine, is low and a control of the efficiency for the achievement of a high efficiency even in the lower speed ranges is not possible as a result of the dependence of the rotational speed on the internal combustion engine.
From EP 0 235 609 A1 a free-running pressure wave charger with a rotor housing and a cell rotor within the rotor housing is described which is provided with cell walls which are axially parallel or disposed helically or inclined to the rotor axis and where air inlet and exhaust air ducts are arranged in the two face sides of the rotor housing. The drive of the cell rotor is performed by charging the cell walls with high-pressure exhaust gases which open into the rotor housing at a respective charging angle by way of gas ducts and the cell rotor is made to rotate by the entry of the exhaust gas. This requires additional ducts in the face side walls which cause an impairment in the positioning and arrangement of the charge air and exhaust gas ducts. Accordingly, the optimal arrangement of the charge air and exhaust gas ducts for a high efficiency of the pressure wave charger is not possible.
From EP 0 143 956 A1 a pressure wave machine with a cell rotor in cast arrangement is known which after the production is subjected to an inner coating with a catalytic material for the reduction of the pollutants contained in the exhaust gases. As a result of the strong turbulence in the cell rotor caused by the dynamic pressure process, an intimate contact arises between the catalyst and the gas and there is a favorable oxidation effect in connection with an oxygen enrichment by contact with the spray air and thus a detoxification of the exhaust gas. The disadvantages aspect is the complex coating process which requires and additional production stage for the cell rotor and the thus occuring thermal stresses for the cell rotor during the coating, thus requiring a massive arrangement of the cell rotor.
It is the object of the present invention to provide a supercharging arrangement for an internal combustion engine with which a high efficiency and thus in total a reduction of energy is achieved over the highest possible speed range of the internal combustion engine.